High-power IGBT Modules
for Industrial Use
Takashi Nishimura
Hideaki Kakiki
Takatoshi Kobayashi
1. Introduction
Power devices used in industrial-use high capacity
inverter system applications are predominately GTO
(gate turnoff) thyristors, which easily handle high
voltages and currents. However, recent advances in
high-voltage and high-power technology for IGBT
(insulated gate bipolar transistor) modules have been
remarkable, and IGBT modules are being used nowadays in applications that had previously required the
use of GTO thyristors.
IGBT modules have an
insulated module structure that differs from the pressure contact structure of a GTO thyristor and that
facilitates assembly, use and maintenance, and as a
result, the field of IGBT module applications is expanding exponentially.
In response to the diversifying needs of recent
years, Fuji Electric has been actively developing products for the recently growing market of high-power
applications.
Targeting high-power industrial-use applications,
Fuji Electric has equipped its U4-series of chips
(hereafter referred to as U4-chips), an improved version of its U-series of chips (hereafter referred to as Uchips), with a copper base to develop high-power IGBT
modules having current capacities of 1,600 A for a 130
× 140 (mm) (1-in-1 and 2-in-1) package and 3,600 A for
a 190 × 140 (mm) (1-in-1) package, and high-voltage
ratings of 1,200 V and 1,700 V. This paper introduces
the summary and technical development of the modules.
Table 1 Fuji Electric’s product lineup of high-power IGBT
modules
Model number
Rated Rated
voltage current
(A)
(V)
1MBI1200U4C-120
1MBI1600U4C-120
1 in 1
1,200
1,200
1MBI2400U4D-120
2,400
1MBI3600U4D-120
3,600
1MBI1200U4C-170
1,200
1MBI1600U4C-170
1,700
1,600
1MBI2400U4D-170
2,400
1MBI3600U4D-170
3,600
2MBI600U4G-120
2MBI800U4G-120
2 in 1
1,600
2MBI600U4G-170
600
1,700
3. Electrical Characteristics
Electrical characteristics of modules that use U4-
High-power IGBT Modules for Industrial Use
M142
190 × 140 × 38
M143
130 × 140 × 38
M142
190 × 140 × 38
M143
130 × 140 × 38
M248
800
1,200
Fig.1 External view of Fuji Electric’s high-power IGBT
modules
M143 package
2. Product Lineup
Table 1 shows Fuji Electric’s product lineup of
high-power IGBT modules. The module lineup consists
of 1,200 V and 1,700 V voltage classes, three types of
packages, and current ratings of 600 to 3,600 A among
a total of 14 types of products. Figure 1 shows an
external view of the packages.
130 × 140 × 38
800
1,200
2MBI1200U4G-170
Package
type
600
1,200
2MBI1200U4G-120
2MBI800U4G-170
Package size
(mm)
M248 package
M142 package
chips are described below in comparison to modules
that use U-chips, and the 2MBI1200U4G-170 (2-in-1
1,200 A / 1,700 V) is presented at the representative
model.
53
electrical characteristics.
3.1 Absolute maximum ratings and electrical characteristics
Table 2 lists the absolute maximum ratings and
Table 2 Maximum ratings and electrical characteristics
(model No.: 2MBI1200U4G-170)
(a) Maximum ratings (Tj = Tc = 25°C, unless otherwise specified)
Item
Symbol
Condition
Maximum
rating
Unit
Collector –
emitter voltage
VCES
VGE = 0 V
1,700
V
Gate – emitter
voltage
VGES
–
±20
V
Collector
current
IC(DC)
ContinTc = 80°C
uous
1,200
A
2,400
A
IC(pulse) 1 ms
Max. power
dissipation
Tc = 80°C
PC
1 device
4,960
W
Max. junction
temperature
Tj max
–
150
°C
Storage
temperature
Tstg
–
-40 to +125
°C
Isolation
voltage
Viso
AC : 1 ms
3,400
V
(b) Electrical characteristics
(Tj = Tc = 25°C, unless otherwise specified)
Symbol
Test condition
Zero gate
voltage
collector
current
Item
Min. Typ. Max. Unit
ICES
VGE = 0 V
Tj = 125°C
VCE = 1,700 V
–
–
1.0
mA
Gate –
emitter
leakage
current
IGES
VGE = ± 20 V
–
–
1.6
µA
Figure 2 shows the VCE(sat) – IC characteristics and
Fig. 3 shows the VF – IF characteristics. The saturation
voltage of the IGBT chip was designed to decrease the
injection efficiency of the pnp transistor, and without
applying lifetime control, to increase the transport
efficiency and provide a positive temperature coefficient. Moreover, by optimizing lifetime control of the
FWD (free wheeling diode) chip, the forward on-voltage
is provided with a positive temperature coefficient as
in the IGBT, and this is advantageous for parallel
connections to both the IGBT chip and the FWD chip.
3.3 Switching characteristics
(1) Turn-on characteristic
Modules that use the U4-chip employ a new
structure in order to optimize the balance between
input capacitance (Cies ) and reverse transfer capacitance (Cres ), and as a result, their turn-on loss is
drastically reduced. Figure 4 shows turn-on waveforms
for an inductive load under the conditions of VCC =
900 V, IC = 1,200 A, Rgon = 1.8 Ω and T j = 125°C.
When driven with the same gate resistance (Rgon), the
module that used the U4-chip (U4-module) had a
smaller tail voltage and approximately 50 % less turnon loss (Eon) than the module that used the U-chip (UFig.2 VCE(sat) – IC characteristics
1,400
VGE = +15 V
Gate –
emitter
threshold
voltage
VGE(th)
Collector –
emitter
saturation
voltage
(sence
terminal)
VGE = Tj = 25°C
VCE(sat) +15 V
IC =
1,200 A Tj = 125°C
ton
Turn-off
time
toff
Forward
on-voltage
(sence
terminal)
Reverse
recovery
time
tr
tf
VF
5.5
6.5
2.25
–
7.5
–
2.65
–
–
110
–
VCC = 900 V
IC = 1,200 A
VGE = ± 15 V
RG = + 4.7 / - 1.2 Ω
Tj = 125°C
–
3.10
–
–
1.25
–
–
1.45
–
–
0.25
–
VGE = T = 25°C
j
0V
IF =
1,200 A Tj = 125°C
–
1.80
–
–
2.00
–
VCC = 900 V
IF = 1,200 A
Tj = 125°C
Thermal resistance
(for 1 device)
Symbol
Rth(j-c)
400
nF
µs
0.45
–
0
0.5
1
1.5
2
VCE (sat) (V)
2.5
3
3.5
Fig.3 VF – I F characteristics
1,400
1,200
V
–
Tj = 125°C
600
0
VGE = 0 V
VCE = 10 V
f = 1 MHz
Tj = 25°C
800
200
1,000
µs
Tj = 25°C
Tj = 125°C
800
600
400
(c) Thermal characteristics
Item
1,000
V
–
t rr
V
IC (A)
VCE = 20 V
IC = 1.2 A
Cies
Turn-on
time
1,200
IF (A)
Input
capacitance
54
3.2 V - I characteristics
CondiMin. Typ.
tion
Max.
Unit
200
0
IGBT
–
–
0.0252
FWD
–
–
0.042
K/W
0
0.5
1
1.5
VF (V)
2
2.5
3
Vol. 52 No. 2 FUJI ELECTRIC REVIEW
Fig.4 Turn-on waveforms (VCC = 900 V, I C = 1,200 A, 125°C)
U4-module
Fig.7 Low-current reverse recovery characteristics
Tj = 25°C, VCC = 1,200 V, Lm = 75 nH,
Rgon = 0.68 Ω, VGE = +15 V /-15 V
VGE : 20 V / div
10,000
0V
U-module
IC : 500 A / div
U-module
VCE : 500 V / div
U-module
di/dt (A/µs)
8,000
6,000
4,000
U4-module
0
0 V, 0 A
U4-module
2,000
t : 500 ns / div
0
25
50
75
100 125
IF (A)
150
175
200
225
175
200
225
(a) di / dt – IF
Tj = 25°C, VCC = 1,200 V, Lm = 75 nH,
Rgon = 0.68 Ω, VGE = +15 V /-15 V
Fig.5 Turn-off waveforms (VCC = 900 V, I C = 1,200 A, 125°C)
2,000
U-module
VGE : 20 V / div
U4-module
U-module
1,500
Vsp (V)
0V
1,000
U4-module
500
IC : 500 A / div
VCE : 500 V / div
0
0
25
50
75
100 125
IF (A)
150
(b) Vsp – IF
0 V, 0 A
t : 500 ns / div
Fig.8 Low-current reverse recovery waveforms
(VAK = 1,200 V, I F = 10 A, 25°C)
Fig.6 PWM inverter power loss simulation
U-module : Vsp = 1,740 V
2,500
U4-module : Vsp = 1,280 V
Loss (W)
2,000
1,901W
Err
1,500
VF
1,000
Eoff
VAK : 500 V / div
1,710W
0 V, 0 A
Eon
IF : 200 A / div
500
VCE(sat)
0
U
U4
(a) Generation mode (cos φ = 0.9)
2,500
2,000
1,825W
Loss (W)
1,575W
1,500
1,000
500
0
U
U4
(b) Regeneration mode (cos φ = - 0.9)
module).
(2) Turn-off characteristic
Figure 5 shows turn-off waveforms for an inductive
load under the conditions of VCC = 900 V, IC = 1,200 A,
High-power IGBT Modules for Industrial Use
Rgoff = 1.2 Ω and T j = 125°C. When driven with the
same gate resistance (Rgoff), the turn-off loss was
approximately 5 % lower for the U4-module than for
the U-module.
(3) PWM inverter power loss simulation
Figure 6 shows the results of a simulation of
inverter power loss when operated under the same
conditions (Iout = 860 A rms, cosφ = 0.9 and - 0.9, fc =
2.5 kHz). The power loss generated in the U4-module
was approximately 10 % less during generation mode
and approximately 14 % less during regeneration mode
than that of the U-module.
(4) Low-current reverse recovery characteristics
The characteristic features of U4-modules, reduced
low-current turn-on di /dt and improved gate resistance controllability of the turn-on di/ dt, enable suppression of the surge voltage at the event of reverse
55
recovery. Figure 7 shows the low-current reverse
recovery characteristics. It can be seen that the lowcurrent turn-on di /dt is smaller and that surge voltage
is suppressed to a greater extent for the U4-module in
comparison to the U-module. Figure 8 shows waveforms obtained under the conditions of VAK = 1,200 V,
I F = 10 A, and Rgon = 0.68 Ω. From this figure and
from Fig. 7(b), it can be seen that the surge voltage is
decreased from 1,740 V to 1,280 V.
4. Package Technology for High-power IGBT
Modules
High capacity inverter systems require high reliability, and ensuring the reliability of the power
devices used to construct such systems is extremely
important. To realize power devices with greater
capacity, it is necessary that many chips be connected
in parallel inside a module, and it is important that
the current balance and generation of heat are maintained with an equal distribution.
4.1 Chip characteristics
As described in paragraph 3.2, high-power IGBT
modules are equipped with chips having a positive
temperature coefficient. In chips having a positive
temperature coefficient, a rise in the junction temperature causes voltage to increase, and therefore current
is self-regulated in order to equalize the junction
temperature in chips connected in parallel. This
characteristic is used to configure stably operating
modules.
a high-power IGBT module.
4.3 Optimization of main terminal structure
The following three factors are important in the
design of the main terminal structure.
(1) Equalization of current balance among DCB substrates
(2) Reduction of internal inductance
(3) Suppression of temperature rise due to heat
generated at main terminal
These three factors involve complex mutually
interacting tradeoff relations, and an optimized design
that satisfies the requirements of all three of these
factors is indispensable.
(1) Equalization of current balance
The DCB substrate is divided from the location of
the module’s main terminal into a portion located
directly below the emitter terminal and a portion
located directly below the collector terminal, and these
must be connected in parallel with the shortest wiring
possible. However, the implementation of the shortest
possible wiring results in a structure prone to inductance imbalance between DCB substrates, and a large
current imbalance will occur during switching (turnon, turn-off, and reverse recovery). Figure 10 shows
the difference of currents flowing to the DCB substrate
in the case of an inductance imbalance and in the case
of balanced inductance. To balance the inductance,
Fig.10 Measurement of current between DCB substrates
200 V/div, 200 A/div, 2 µs/div
4.2 Divided DCB substrate
High-power IGBT modules are configured with a
maximum of twenty-four IGBT and FWD chips, each,
which are connected in a parallel configuration. In
order to ensure power cycle capability and to improve
mass productivity, a structure is adopted that divides
the DCB (direct copper bonding) substrate. By dividing the DCB substrate, thermal interference can be
reduced and the quality of each DCB substrate can be
checked individually, and as a result, productivity can
be increased. Figure 9 shows the internal structure of
Composite current (IC1 + IC2)
VCE
IC2 : DCB2 current
0 V, 0 A
IC1 : DCB1 current
(a) Inductance imbalance
200 V/div, 200 A/div, 2 µs/div
Fig.9 Internal structure
Emitter terminal
Composite current (IC1 + IC2)
VCE
IC2 : DCB2 current
0 V, 0 A
Collector terminal
56
Divided DCB
substrate
IC1 : DCB1 current
(b) Balanced inductance
Vol. 52 No. 2 FUJI ELECTRIC REVIEW
Fig.11 ∆T j power cycle capability
temperature rise due to the heat generated by a
terminal during current conduction can be suppressed
is an issue. By forming the emitter and collector
terminals with an outward curvature at their part
inside module, the volume of each terminal increases
and the temperature rise due to generated heat during
current conduction is suppressed.
109
Number of cycles (cycle)
108
107
5. Ensuring the Power Cycle Capability
106
105
104
103
10
100
∆ Tj (°C)
1,000
current pathways inside the emitter terminal and
collector terminal were analyzed, and a structure was
adopted that balances the current.
(2) Reduction of internal inductance
High-power IGBT modules require the capability
to instantaneously turn-off a large current, and it is
important to reduce the surge voltage generated inside
the package at the event of turn-off. In other words,
decreasing the internal inductance of the package
becomes an issue. However, the structure described in
the above paragraph and introduced to equalize the
current balance has the contrary effect of increasing
the internal inductance, but by actively utilizing
magnetic field interactions, individual inductances can
be cancelled and the increase in inductance suppressed. As a result, an extremely small inductance
per terminal of approximately 20 nH was realized.
(3) Suppression of temperature rise due to heat
generated at main terminal
The main terminal of a high-power IGBT module is
required to provide the capability to conduct 1,200 A of
current per terminal (single terminal configured from
the emitter and collector terminals) in order to configure a 3,600 A (max.) module. The extent to which
High-power IGBT Modules for Industrial Use
From the analysis of an IGBT module after power
cycle testing, Fuji Electric has verified that the ∆T j
power cycle capability is determined by the combined
lifetimes of the under-the-chip solder and the bonding
wire. In a high-power IGBT module, by using the
higher stiffness material of Sn-Ag as the under-thechip solder, dividing the DCB substrate to suppress
thermal interference, and equalizing current flow
among DCB substrates, we verified that the ∆T j power
cycle capability is equal to that of a module having few
parallel connections (See Fig. 11). Moreover, we conducted a ∆Tc power cycle test assuming a specific
application for high-power IGBT modules in which the
case temperature varied widely, and verified the
capability to withstand 10,000 cycles at ∆Tc = 70°C.
6. Conclusion
An overview of Fuji Electric’s high-power IGBT
module products that use U4-chips has been presented.
We are confident that this product group will be able to
provide through support of diversified needs.
In
particular, the reduction in turn-on loss enables a
wider range of choices for the gate resistance and
improves the ease of use. Fuji Electric remains
committed to raising the level of power semiconductor
and package technology in order to support additional
needs and to developing new products that contribute
to the advancement of power electronics.
Reference
(1) Morozumi, A. et al. Reliability of Power Cycling for
IGBT Power Semiconductor Module. Conf. Rec. IEEE
Ind. Appl. Conf. 36th. 2001, p.1912-1918.
57